Image sensor having a time calculator and image processing device including the same

ABSTRACT

Provided are an image sensor and an image processing device including the same. The image sensor includes: a pixel array including a plurality of pixels arranged in rows and columns and configured to generate pixel signals from the plurality of pixels, a time calculator configured to receive zoom information corresponding to digital zooming, and configured to calculate a row processing time available for processing the pixel signals from the plurality of pixels included in a single row based on the zoom information, a timing generator configured to generate at least one control signal based on the row processing time; and an Analog-to-Digital Converter (ADC) configured to generate pixel data by performing sampling on the pixel signals according to the at least one control signal.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2017-0046298, filed on Apr. 10, 2017, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

Inventive concepts relate to an image sensor, and more particularly, toan image sensor that may reduce noise during digital zooming and mayreduce power consumption.

An image sensor may convert a light signal including image informationof an object to an electrical signal. Widely used image sensors includea charge-coupled device (CCD) image sensor and a complementarymetal-oxide semiconductor (CMOS) image sensor. With the development ofthe computer industry and the telecommunications industry, demand hasincreased for image sensors with improved performance in variouselectronic devices, such as digital cameras, camcorders, personalcommunication systems (PCS), game devices, security cameras, medicalmicro-cameras, and/or mobile phones.

In order to enlarge an image for an image sensor, optical zooming, whichenlarges an image by adjusting a distance between lenses, and digitalzooming, which enlarges an image by cutting out a portion of the imageduring shooting, may be used. In digital zooming, a new pixel value isinterpolated using an existing image value when a zoom function isperformed, and as a result of these characteristics, digital zoomingshows a less delicate image than that shown by the optical zooming.Therefore, various studies are being conducted to reduce deteriorationof an image during digital zooming.

SUMMARY

Inventive concepts provide an image sensor that may reduce noise duringdigital zooming and prevents image deterioration and an image processingdevice including the same.

Inventive concepts provide an image sensor that may reduce powerconsumption during digital zooming and an image processing deviceincluding the same.

According to an example embodiment of inventive concepts, there isprovided an image sensor including a pixel array including a pluralityof pixels arranged in rows and columns and configured to generate pixelsignals from the plurality of pixels, a time calculator configured toreceive zoom information corresponding to digital zooming, andconfigured to calculate a row processing time available for processingthe pixel signals from the plurality of pixels included in a single rowbased on the zoom information, a timing generator configured to generateat least one control signal based on the row processing time; and anAnalog-to-Digital Converter (ADC) configured to generate pixel data byperforming sampling on the pixel signals according to the at least onecontrol signal.

According to an example embodiment of inventive concepts, there isprovided an image processing device including an image processorconfigured to calculate a row processing time available for processingpixel signals for a plurality of pixels included in a single row basedon zoom information corresponding to digital zooming; and an imagesensor including a timing generator configured to generate at least onecontrol signal based on the row processing time, and an ADC configuredto generate pixel data by performing sampling on the pixel signalsaccording to the at least one control signal.

According to an example embodiment of inventive concepts, there isprovided a computer system including an image processor configured toadaptively adjust an adjusted row processing time in response toreceiving a digital zoom command and an image sensor configured tosample an image according to the adjusted row processing time.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of inventive concepts will be more clearlyunderstood from the following detailed description taken in conjunctionwith the accompanying drawings in which:

FIG. 1 is a block diagram of an image processing device according to anexample embodiment of inventive concepts.

FIG. 2 is a flowchart of a method of operating a time calculatoraccording to an example embodiment of inventive concepts.

FIG. 3 is a block diagram of an image sensor according to an exampleembodiment of inventive concepts.

FIG. 4 is a block diagram of an image sensor according to an exampleembodiment of inventive concepts.

FIG. 5 is a view of an original image according to an example embodimentof inventive concepts and a digital zoom image obtained by digitalzooming performed on the original image.

FIG. 6 is a graph of a row processing time for a digital zoommagnification, according to an example embodiment of inventive concepts.

FIG. 7 is a block diagram of an image sensor according to an exampleembodiment of inventive concepts.

FIG. 8 is a flowchart of a method of operating an image sensor accordingto an example embodiment of inventive concepts.

FIG. 9A is a timing diagram of a multi-sampling operation according toan example embodiment of inventive concepts.

FIG. 9B is a timing diagram of a multi-sampling operation according toan example embodiment of inventive concepts.

FIGS. 10A and 10B are views of a method of determining the number oftimes of sampling according to an example embodiment of inventiveconcepts.

FIG. 11 is a block diagram of an image sensor according to an exampleembodiment of inventive concepts.

FIG. 12 is a flowchart of a method of operating a capacitance adjustingunit according to an example embodiment of inventive concepts.

FIG. 13 is a block diagram of an image sensor according to an exampleembodiment of inventive concepts.

FIG. 14 is a block diagram of an image sensor according to an exampleembodiment of inventive concepts.

FIG. 15 is a block diagram of an image sensor according to an exampleembodiment of inventive concepts.

FIG. 16 is a block diagram of an image processing device according to anexample embodiment of inventive concepts.

FIG. 17 is a block diagram of a computing system including an imagesensor, according to an example embodiment of inventive concepts.

DEAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 is a block diagram of an image processing device 10 according toan example embodiment of inventive concepts.

Referring to FIG. 1, the image processing device 10 may include an imageprocessor 100 and an image sensor 200.

The image processor 100 may process image data sensed and output by theimage sensor 200, and output the processed image data to a displaydevice. The image processor 100 may process image data to fit humaneyes. The display device may include a device capable of outputting animage (e.g., a computer, a mobile phone, or an electronic device havinga camera). The image processor 100 may be implemented, for example, as adigital signal processor (DSP), an image signal processor (ISP), and/oran application processor (AP).

The image processor 100 may receive a digital zoom command CMD_DZ from auser or a host. The digital zoom command CMD_DZ may include zoominformation ZI according to digital zooming. The image processor 100 mayextract the zoom information ZI from the received digital zoom commandCMD_DZ, and output the extracted zoom information ZI to a timecalculator 210.

In an example embodiment, the zoom information ZI may include at leastone of information about an image size corresponding to an image to beoutput to the display device, information about a pixel address at whichan image to be output is formed, and information about a digital zoommagnification, wherein the information about the image size may includethe row number of a plurality of pixels to which data for the image tobe output is input. This will be described later below with reference toFIG. 5.

The image sensor 200 may sense intensity of light of an object capturedthrough a lens under the control of the image processor 100, and mayconvert the intensity of the sensed light into digital image data. Theimage sensor 200 may output the digital image data to the imageprocessor 100. The image sensor 200 may include a time calculator 210, atiming generator 220, and an analog-to-digital converter (ADC) 230.

The time calculator 210 may calculate a row processing time RPT based onthe zoom information ZI received from the image processor 100 and outputthe calculated row processing time RPT to the timing generator 220. Therow processing time RPT may be the time taken for an image sensor toprocess a single row, and RPT=1/FPS×RN (where RPT is the row processingtime, FPS is a frame rate per second, and RN is a row number,hereinafter referred to as a row processing time calculation formula).The row processing time RPT may also be referred to as one horizontaltime (1H-time). According to an example embodiment of inventiveconcepts, the time calculator 210 may use the row number RN changed incorrespondence with digital zooming in calculating the row processingtime RPT,

According to an example embodiment of inventive concepts, a referencerow processing time may be used when the time calculator 210 calculatesthe row processing time RPT. The reference row processing time may meanor may correspond to the row processing time RPT when digital zooming isnot performed, for example, when the magnification is 1×. In an example,the time calculator 210 may calculate a value obtained by multiplyingthe reference row processing time by the magnification as the rowprocessing time RPT.

The timing generator 220 may output a sampling control signal Cont_SP tothe ADC 230 based on the received row processing time RPT. The ADC 230may perform sampling on a pixel signal including image data for anobject to be observed based on the received sampling control signalCont_SP. Although FIG. 1 illustrates the time calculator 210 separatelyfrom the timing generator 220, inventive concepts are not limitedthereto. The timing generator 220 may serve as the time calculator 210according to example embodiments.

FIG. 2 is a flowchart of a method of operating the time calculator 210according to an example embodiment of inventive concepts.

Referring to FIG. 2, in operation S110, the time calculator 210 mayreceive the zoom information ZI from the image processor 100. Thereceived zoom information ZI may include at least one of informationabout an image size corresponding to an image to be output to thedisplay device, information about a pixel address to which data for theimage to be output is input, and/or information about a digital zoommagnification, wherein the information about the image size may includethe row number of a plurality of pixels to which data for the image tobe output is input.

In operation S120, the time calculator 210 may calculate the rowprocessing time RPT based on the received zoom information ZI. In anexample, when the received zoom information ZI includes informationabout the row number which has changed in correspondence with thedigital zooming, the time calculator 210 may substitute the changed rownumber into the row processing time calculation formula to calculate therow processing time RPT. In an example, when the received zoominformation ZI includes information about the pixel address, the timecalculator 210 may calculate the changed row number through the receivedpixel address and calculate the row processing time RPT by substitutingthe changed row number into the row processing time calculation formula.In an example, when the received zoom information ZI includes theinformation about magnification, the time calculator 210 may calculate,as the row processing time RPT, a value obtained by multiplying areference row processing time by the magnification.

In operation S130, the time calculator 210 may output the calculated rowprocessing time RPT to the timing generator 220. The timing generator220 may adjust operation timing of the ADC 230 and/or similar itemsbased on the received row processing time RPT.

FIG. 3 is a block diagram of the image sensor 200 according to anexample embodiment of inventive concepts. In FIG. 3, the same referencenumerals as in FIG. 1 denote the same elements, and therefore, repeateddescriptions thereof will not be given herein.

Referring to FIG. 3, the image sensor 200 may include the timecalculator 210, the timing generator 220, the ADC 230, a pixel array240, a row driver 250, a ramp generator 260 and a read-out circuit 280.

The time calculator 210 may receive the zoom information ZI and outputthe row processing time RPT to the timing generator 220. Based on thereceived row processing time RPT, the timing generator 220 may output arow driver control signal Cont_RD to the row driver 250, may output thesampling control signal Cont_SP to the ADC 230 and the read-out circuit280, and may output a ramp-control signal Cont_RP to the ramp generator260. Thus, the timing generator 220 may adjust operation timing of therow driver 250, the ADC 230, the read-out circuit 280, and the rampgenerator 260, based on the row processing time RPT.

The row driver 250 may drive the pixel array 240 in row units. Forexample, the row driver 250 may generate a transmission control signalfor controlling transmission transistors of each unit pixel constitutingthe pixel array 240, a reset control signal for controlling a resettransistor, a selection control signal for controlling a selectiontransistor, and the like. According to an example embodiment ofinventive concepts, in response to the row driver control signal Cont_RDof the timing generator 220 during digital zooming, the row driver 250may drive at least some rows of the pixel array 240.

The pixel array 240 may include a plurality of photoelectric conversionelements such as photo diodes and/or pinned photo diodes, and mayfurther include a plurality of pixels arranged in rows and columns. Thepixel array 240 may sense light using the plurality of photoelectricconversion elements and convert the light into an electrical signal togenerate a pixel signal VPixel. The pixel array 240 may output the pixelsignal VPixel including a reset signal and a video signal from a rowline selected by a row selection signal provided from the row driver 250to the ADC 230.

The ADC 230 may convert the pixel signal VPixel in an analog domainreceived from the pixel array 240 into pixel data PD in a digitaldomain. To this end, the ADC 230 may include a comparator 231 and acounter 232.

The comparator 231 may receive a ramp signal RP from the ramp generator260, and may compare the received ramp signal RP with the pixel signalVPixel and output a comparison result signal to the counter 232. Thecounter 232 may count time from when the sampling control signal Cont_SPis received from the timing generator 220 to when the comparison resultsignal is received from the comparator 231 and generate the pixel dataPD corresponding thereto. The counter 232 may output the generated pixeldata PD to the read-out circuit 280. The read-out circuit 280 maygenerate the image data ID based on the received pixel data PD andoutput the image data ID to the image processor 100 (of FIG. 1).

The ramp generator 260 may receive the ramp-control signal Cont_RP fromthe timing generator 220 and generate the ramp signal RP based thereon.Furthermore, the ramp generator 260 may output the generated ramp signalRP to the comparator 231.

According to inventive concepts, during the digital zooming, the timecalculator 210 may adaptively adjust the row processing time RPT bycalculating the row processing time RPT based on the zoom informationZI, and the timing generator 220 may adjust the operation timing of theADC 230, the row driver 250, the ramp generator 260, the read-outcircuit 280, etc. according to the adjusted row processing time RPT sothat the row processing time RPT for processing a single row may beprolonged.

FIG. 4 is a block diagram of the image sensor 200 according to anexample embodiment of inventive concepts. In more detail, FIG. 4 is ablock diagram of the ADC 230, the pixel array 240, the row driver 250,the ramp generator 260, and the read-out circuit 280 in the image sensor200. In FIG. 4, the same reference numerals as in FIG. 3 denote the sameelements, and therefore, repeated descriptions thereof will not be givenherein.

The pixel array 240 may include a plurality of unit pixels PX in theform of a matrix connected to a plurality of row lines ROW1 to ROWm anda plurality of column lines COLI to COLn, respectively. The pixel arraymay be formed by stacking, e.g. vertically stacking, a semiconductorsubstrate, an interlayer insulating layer, a color filter layer, andmicro-lenses. For example, the semiconductor substrate may be or mayinclude a semiconductor substrate on which a p-type epitaxial layer isformed on a p-type bulk silicon substrate, and photodiodes may be formedby injecting, e.g. implanting, n-type ions into the p-type epitaxiallayer. In addition, the interlayer insulating layer may be stacked onthe semiconductor substrate. The interlayer insulating layer may includegates of transistors included in unit pixels and conductive lines ofmultiple layers. According to the example embodiment, a protective layerfor protecting elements may be stacked on the interlayer insulatinglayer. The color filter layer may be stacked on the interlayerinsulating layer (or the protective layer), and the color filter layermay include a plurality of color filters. In an example embodiment, aBayer pattern technique may be applied to the color filter layer. Forexample, the color filters may include at least one red filter, at leastone green filter, and at least one blue filter, or at least one magentafilter, at least one cyan filter, and at least one yellow filter.According to an example embodiment, a flat layer called an overcoatlayer may be stacked on the color filter layer. The micro-lenses arestacked on the color filter layer (or the flat layer) and may guideincident light so that the incident light is efficiently incident onphotodiodes of unit pixels.

Each of, or at least some of, the plurality of unit pixels PX mayinclude at least one of a red pixel for converting light in a redspectral region into an electrical signal, a green pixel for convertinglight in a green spectral region into an electrical signal, a blue pixelfor converting light in a blue spectral region into an electricalsignal, and a depth pixel for converting depth information into anelectrical signal using a Time Of Flight (TOF) method. For example, eachof the plurality of unit pixels PX may output pixel signals havingdifferent voltage levels according to intensity of incident light.

The row driver 250 may decode the row driver control signal Cont_RDgenerated in the timing generator 220 and may select at least one of therow lines included in the pixel array 240 in response to the decoded rowdriver control signal Cont_RD. For example, the row driver 250 mayselect and drive the first to m^(th) row lines ROW1 to ROWm in responseto the row driver control signal Cont_RD According to an exampleembodiment of inventive concepts, the row driver 250 may select anddrive only a portion corresponding to the row driver control signalCont_RD from among the first to m^(th) row lines ROW1 to ROWm duringdigital zooming. Accordingly, the image sensor 200 according toinventive concepts may set the row processing time RPT to be longer thana reference row processing time because the row driver 250 drives onlysome of the rows while maintaining a constant frame rate per second(fps) with respect to driving of a single frame constant during thedigital zooming.

Each of, or at least some of, the comparators 231 may be connected toany one of the first to n^(th) column lines COL1 to COLn and the rampgenerator 260. Any one of the first to n^(th) column lines COL1 to COLnmay be connected to a first input terminal of a comparator 231, and theramp generator 260 may be connected to a second input terminal of acomparator 231. Each of the comparators 231 may receive a pixel signalreceived from one of the first to n^(th) column lines COL1 to COLn and aramp signal value generated from the ramp generator 260, compare themwith each other, and output a comparison result signal to an outputterminal of each of the comparators 231. A difference between a signalsample and a reset sample in the comparison result signal output fromthe comparator 231 may be picked up and output according to a gradientof a ramp signal. The ramp generator 260 may be operated based on theramp-control signal Cont_RP generated in the timing generator 220. Thiswill be described later with reference to FIGS. 9A and 9B.

Each counter 232 may be connected to the output terminal of eachcomparator 231. The counter 232 may include an up/down counter and abit-wise inversion counter. As described above, the each counter 232 maycount time from when the sampling control signal Cont_SP is receivedfrom the timing generator 220 to when the comparison result signal isreceived from the comparator 231 and generate the pixel data PD in adigital domain corresponding thereto.

The read-out circuit 280 may include a plurality of memories 281. Eachof the plurality of memories 281 may store pixel data received from theADC 230 based on the sampling control signal Cont_SP generated by thetiming generator 220. Each of the plurality of memories 281 maycorrespond to static random-access memory (SRAM), but inventive conceptsis not limited thereto. A memory 281 may output image data in thedigital domain to the image processor 100.

FIG. 5 is a view of an original image according to an example embodimentof inventive concepts and a digital zoom image obtained by digitalzooming performed on the original image. In more detail, FIG. 5 is aview of an original image and a digital zoom image produced from axdigital zooming performed on the original image.

Referring to FIG. 5, a user or a host may output a command to an imageprocessing device to perform the ax digital zooming to enlarge a firstarea Area 1 of the original image. Data for the first area may be formedin some of a plurality of pixels PX included in the pixel array 240.

When processing an original image without digital zooming, the imageprocessing device may acquire data from the plurality of pixels PXconnected to N column lines and M row lines, and output image data to adisplay device. Alternatively, when processing an original image with axdigital zooming, the image processing device may acquire data from theplurality of pixels PX connected to N/a column lines and M/a row linescorresponding to the first area Area 1, and output image data to thedisplay device using the acquired data. Therefore, even when digitalzooming is performed, when the same row processing time RPT is used, theimage processing device outputs a digital zoom image to the displaydevice by utilizing limited data as compared with the original image.Therefore, image quality deterioration due to a variety of noise mayoccur in an interpolation process.

According to inventive concepts, since the original image and thedigital zoom image are the same in terms of a frame rate per second(fps) for processing a single frame, the total frame processing time ofthe original image may be the same as that of the digital zoom image.Thus, the row processing time RPT of the digital zoom image may be setto be longer than the row processing time (RPT) of the original image ifthe original image has a small row number to be processed. Accordingly,the total frame processing time may be set to be the same as that of theoriginal image. According to an example embodiment of inventiveconcepts, image deterioration of the digital zoom image may be reducedby having the row processing time RPT longer, so as to reduce noisecausing image deterioration.

FIG. 6 is a graph of the row processing time RPT for a digital zoommagnification, according to an example embodiment of inventive concepts.

A horizontal axis in FIG. 6 may be the digital zoom magnification and avertical axis may be the row processing time RPT. Referring to FIG. 6,when the digital zooming is not performed corresponding to when themagnification is nix, the row processing time RPT may be first timeRPT1. Furthermore, the row processing time RPT when the magnification isn2× may be second time RPT2 and the row processing time RPT when themagnification is n3× may be third time RPT3. According to an exampleembodiment of inventive concepts, the row processing time RPT may beproportional to the magnification. Although FIG. 6 shows that the rowprocessing time RPT is proportional to magnification of a linearfunction, inventive concepts are not limited thereto.

FIG. 7 is a block diagram of an image sensor 200 a according to anexample embodiment of inventive concepts. In FIG. 7, the same referencenumerals as in FIG. 3 denote the same elements, and therefore, repeateddescriptions thereof will not be given herein.

Referring to FIG. 7, the image sensor 200 a may include a timecalculator 210 a, a timing generator 220 a, an ADC 230 a, a rampgenerator 260 a, and a multi-sampling unit 291 a.

The time calculator 210 a may output the row processing time RPTcalculated based on the received zoom information ZI to themulti-sampling unit 291 a. The multi-sampling unit 291 a may determinethe number of times of sampling based on the received row processingtime RPT. The multi-sampling unit 291 a may output a multi-samplingenable signal En_MS including information on the determined number oftimes of sampling to the timing generator 220 a. The timing generator220 a may output the ramp-control signal Cont_RP to the ramp generator260 a, based on the number of times of sampling included in the receivedmulti-sampling enable signal En_MS, and output a multi-sampling controlsignal Cont_MS to the ADC 230 a. The ADC 230 a may performmulti-sampling on the received pixel signal VPixel based thereon andoutput the generated pixel data. PD to the read-out circuit 280 (of FIG.3). The multi-sampling will be described later below with reference toFIGS. 9A and 9B.

An image sensor according to inventive concepts may improve noise of adigital zoom image by determining the number of times of sampling, basedon the row processing time RPT and performing multi-sampling on thepixel signal VPixel.

FIG. 8 is a flowchart of a method of operating an image sensor accordingto an example embodiment of inventive concepts. In FIG. 8, the samereference numerals as in FIG. 7 denote the same elements, and therefore,repeated descriptions thereof will not be given herein.

Referring to FIGS. 7 and 8, in operation S210, the multi-sampling unit291 a may receive, from the time calculator 210 a, the row processingtime RPT calculated based on the zoom information ZI. In operation S220,the multi-sampling unit 291 a may determine the number of times ofsampling based on the received row processing time RPT. In an example,the multi-sampling unit 291 a may determine the number of times ofsampling based on a table stored in advance. In an example, themulti-sampling unit 291 a may determine the number of times of samplingbased on a specific (or, alternatively, predetermined) formula. Thiswill be described later below with reference to FIGS. 10A and 10B.

In operation S230, the multi-sampling unit 291 a may output themulti-sampling enable signal En_MS including information on thedetermined number of times of sampling to the timing generator 220 a, Inoperation S240, the timing generator 220 a may output the multi-samplingcontrol signal Cont_MS for multi-sampling to the ADC 230 a, based on thedetermined number of times of sampling. The multi-sampling controlsignal Cont_MS may include timing control signals for multiple resetsampling and multiple signal sampling. In operation S250, the ADC 230 amay perform multi-sampling on the pixel signal VPixel based on themulti-sampling control signal Cont_MS.

FIG. 9A is a timing diagram of a multi-sampling operation according toan example embodiment of inventive concepts. In more detail, FIG. 9A isa timing diagram of the image sensor 200 a of FIG. 7 performing amulti-sampling operation in which sampling is performed two times toobtain the pixel data PD (of FIG. 3) from one unit pixel PX (of FIG. 4)during the row processing time RPT.

Referring to FIGS. 7 and 9A, the multi-sampling process of the imagesensor 200 a may include an auto-zero section AZ, a reset-samplingsection RESET, and/or a signal-sampling section SIGNAL. During theauto-zero section AZ, the image sensor 200 a may match a level of thepixel signal VPixel with that of the ramp signal RP. During thereset-sampling section RESET, the image sensor 200 a may measure aremaining voltage value in pixels as a reference for obtaining theaccurate pixel data PD (of FIG. 3). A residual voltage value measuredduring the reset-sampling section RESET may vary from pixel to pixel.During the signal-sampling section SIGNAL, the image sensor 200 a mayacquire a signal sample for the pixel data PD (of FIG. 3) obtained byconverting light into an electrical signal. The image sensor 200 aaccording to an example embodiment of inventive concepts may performmulti-sampling by performing reset sampling two or more times during thereset-sampling section RESET and performing signal sampling two or moretimes during the signal-sampling section SIGNAL. FIG. 9A shows a timingdiagram for multi-sampling in which sampling is performed twice. Theramp signal RP may transition to a first voltage level after theauto-zero section AZ has ended.

At a point in time T1, the timing generator 220 a may enter the resetsampling section RESET by transitioning the multi-sampling controlsignal Cont_MS for the ADC 230 a and the ramp-control signal Cont_RP forthe ramp generator 260 a to logic high based on the row processing timeRPT received from the time calculator 210 a. The ramp generator 260 amay lower a voltage level of the ramp signal RP with a constant gradientin response to the ramp-control signal Cont_RP transitioning to logichigh. Also, a counter 232 a may start counting CNT in response to arising edge of the multi-sampling control signal Cont_MS.

A point in time T2 may indicate a point in time when the voltage levelof the ramp signal RP coincides with a voltage level of the pixel signalVPixel. At the point in time T2, a comparator 231 a may output acomparison result signal CR to the counter 232 a, and the counter 232 amay complete the counting CNT accordingly. The counter 232 a may counttime from the rising edge of the multi-sampling control signal Cont_MSto the comparison result signal CR of the comparator 23_la and generatethe counted value as a first reset sample R1.

At a point in time T3, the timing generator 220 a may transition themulti-sampling control signal Cont_MS for the ADC 230 a and theramp-control signal Cont_RP for the ramp generator 260 a to a logic lowvalue (“logic low.”) The ramp generator 260 a may maintain the voltagelevel of the ramp signal RP constant in response to the ramp controlsignal Cont_RP transitioning to logic low.

At a point in time T4, the timing generator 220 a may transition themulti-sampling control signal Cont_MS for the ADC 230 a and theramp-control signal Cont_RP for the ramp generator 260 a to a logic highvalue (“logic high.”) The ramp generator 260 a may raise the voltagelevel of the ramp signal RP with a constant gradient in response to theramp-control signal Cont_RP transitioning to logic high. Also, thecounter 232 a may start the counting CNT in response to the rising edgeof the multi-sampling control signal Cont_MS.

At a point in time T5 when the pixel signal Pixel coincides with theramp signal RP, the comparator 231 a may output the comparison resultsignal CR to the counter 232 a, and the counter 232 a may complete thecounting CNT accordingly. The counter 232 a may count time from therising edge of the multi-sampling control signal Cont_MS to thecomparison result signal CR of the comparator 231 a and generate thecounted value as a second reset sample R2.

At a point in time T6, the timing generator 220 a may complete thereset-sampling section RESET by transitioning the multi-sampling controlsignal Cont_MS for the ADC 230 a and the ramp-control signal Cont_RP forthe ramp generator 260 a to logic low. The ramp generator 260 a maymaintain the voltage level of the ramp signal RP constant in response tothe ramp control signal Cont_RP transitioning to logic low.

The ADC 230 a may perform synthesis for the first reset sample R1 andthe second reset sample R2 generated during the reset sampling sectionRESET. A reset sample may include a reset information term includingsubstantial information and an unnecessary noise term. As they have thesame phase, reset information terms included in each of the first resetsample R1 and the second reset sample R2 are synthesized by a simpleoperation, while noise terms have different phases and are synthesizedthrough an orthogonal operation. A signal quantity to be increased bythe simple operation of the reset information terms may be larger than asignal quantity to be increased through the orthogonal operation of thenoise terms. As a result, a signal-to-noise ratio (SNR) of a resetsample synthesized through multi-sampling may be less than that of areset sample synthesized through a single instance of sampling.

Before entering the signal sampling section SIGNAL and after the resetsampling section RESET is completed according to the control of the rowdriver 250 (of FIG. 3), the pixel array 240 (of FIG. 3) may convert alight signal received from an object into an electrical signal.Accordingly, the voltage level of the pixel signal VPixel may vary.

At a point in time T7, the timing generator 220 a may enter thesignal-sampling section SIGNAL by transitioning the multi-samplingcontrol signal Cont_MS for the ADC 230 a and the ramp-control signalCont_RP for the ramp generator 260 a to logic high based on the rowprocessing time RPT received from the time calculator 210 a. The rampgenerator 260 a may lower a voltage level of the ramp signal RP with aconstant gradient in response to the ramp-control signal Cont_RPtransitioning to logic high. Also, the counter 232 a may start thecounting CNT in response to the rising edge of the multi-samplingcontrol signal Cont_MS.

At a point in time T8 when the pixel signal VPixel coincides with theramp signal RP, the comparator 231 a may output the comparison resultsignal CR to the counter 232 a, and the counter 232 a may complete thecounting CNT accordingly. The counter 232 a may count time from therising edge of the multi-sampling control signal Cont_MS to thecomparison result signal CR of the comparator 231 a and may generate thecounted value as a first signal sample S1.

At a point in time T9, the timing generator 220 a may transition themulti-sampling control signal Cont_MS for the ADC 230 a and theramp-control signal Cont_RP for the ramp generator 260 a to logic low.The ramp generator 260 a may maintain the voltage level of the rampsignal RP constant in response to the ramp control signal Cont_RPtransitioning to logic low.

At a point in time T1.0, the timing generator 220 a may transition themulti-sampling control signal Cont_MS for the ADC 230 a and theramp-control signal Cont_RP for the ramp generator 260 a to logic high.The ramp generator 260 a may raise the voltage level of the ramp signalRP with a constant gradient in response to the ramp-control signalCom_RP transitioning to logic high. Also, the counter 232 a may startthe counting CNT in response to the rising edge of the multi-samplingcontrol signal Com_MS.

At a point in time T11 when the voltage level of the ramp signal RPbecomes equal to the voltage level of the pixel signal Pixel, thecomparator 231 a may output the comparison result signal CR to thecounter 232 a, and the counter 232 a may complete the counting CNTaccordingly. The counter 232 a may count time from the rising edge ofthe multi-sampling control signal Cont_MS to the comparison resultsignal CR of the comparator 231 a and generate the counted value as asecond signal sample S2.

At a point in time T12, the timing generator 220 a may complete thesignal-sampling section SIGNAL by transitioning the multi-samplingcontrol signal Cont_MS for the ADC 230 a and the ramp-control signalCont_RP for the ramp generator 260 a to logic low. The ramp generator260 a may maintain the voltage level of the ramp signal RP constant inresponse to the ramp control signal Cont_RP transitioning to logic low,

The ADC 230 a may perform synthesis for the first and second signalsamples S I and S2 generated during the signal-sampling section SIGNAL.As with the reset sample, the signal sample may include a signalinformation term including substantial information and an unnecessarynoise term, and a signal quantity to be increased by a simple operationof the signal information term may be larger than a signal quantity tobe increased through an orthogonal operation of the noise term.Accordingly, an SNR of a signal sample synthesized throughmulti-sampling may be less than a signal sample synthesized through asingle instance of sampling.

The ADC 230 a may generate a signal sample synthesized with thesynthesized reset sample through a series of the above operations, and adifference between the synthesized signal sample and the synthesizedreset sample may be output to the read-out circuit 280 (of FIG. 3) aspixel data in a digital domain.

FIG. 9A shows an example embodiment in which the ramp control signalCont_RP transitions to logic high when the ramp signal RP starts to riseor fall, and the multi-sampling control signal Cont_MS transitions tologic high when the counting CNBC starts. For example, the ramp controlsignal Cont_RP may transition to logic low when the ramp signal RPstarts to rise or fall, and the multi-sampling control signal Cont_MSmay transition to logic low when the counting CNT starts. Accordingly,the ramp control signal Cont_RP and the multi-sampling control signalCont_MS may operate in the reverse of FIG. 9A. Furthermore, althoughFIG. 9A illustrates a case where reset sampling and signal sampling formulti-sampling are performed twice each, inventive concepts is notlimited thereto. It should be understood that inventive concepts mayalso be applied to a case where sampling is performed three times ormore.

FIG. 9B is a timing diagram of a multi-sampling operation according toan example embodiment of inventive concepts. In more detail, FIG. 9B isanother timing diagram of the image sensor 200 a of FIG. 7 performing amulti-sampling operation in which sampling is performed two times toobtain the pixel data PD (of FIG. 3) from one unit pixel PX (of FIG. 4)during the row processing time RPT. In FIG. 9B, the same referencenumerals as in FIG. 9A denote the same elements, and therefore, repeateddescriptions thereof will not be given herein.

Referring to FIG. 7 and FIGS. 9A and 9B, in FIG. 9B, at the points intime T3 and T9, the ramp signal RP may transition to the first voltagelevel at the end of the auto-zero section AZ. As the ramp signal RPtransitions to the first voltage level as same as the end of theauto-zero section AZ at the points in time T3 and 19, the voltage levelof the ramp signal RP may also be lowered at the points in time T4 andT10 when a rising edge of the ramp control signal Cont_RP occurs inaddition to the points in time and 17. Since the method of operating theimage sensor according to FIG. 9B is similar to or the same as themethod of operating the image sensor according to FIG. 9A, a detaileddescription thereof will not be given herein.

FIGS. 10A and 10B are views of a method of determining the number oftimes of sampling, according to an example embodiment of inventiveconcepts. In more detail, FIG. 10A is a view of a method of determiningthe number of times of sampling according to a formula and/or a graph,and FIG. 10B is a view of a method of determining the number of times ofsampling according to a table.

Referring to FIGS. 7 and 10A., when the multi-sampling unit 291 areceives the row processing time RPT from the time calculator 210 a, thenumber of times of sampling corresponding to the received row processingtime RPT may be determined according to the graph or the formula of FIG.10A. In an example, the graph or the formula may be dynamicallyspecified (or, alternatively, predetermined.) The multi-sampling unit291 a may determine the number of times of sampling as ml when thereceived row processing time RPT is between the first time RPT1 and thesecond time RPT2, determine the number of times of sampling as m2 whenthe received row processing time RPT is between the second time RPT2 andthe third time RPT3, determine the number of times of sampling as m3when the received row processing time RPT is between the third time RPT3and fourth time RPT4, and determine the number of times of sampling asm4 when the received row processing time RPT is greater than the fourthtime RPT4.

Referring to FIGS. 7 and 10B, when the multi-sampling unit 291 areceives the row processing time RPT from the time calculator 210 a, thenumber of times of sampling corresponds to a row processing time table.The row processing time table may be stored in a memory inside the imagesensor 200 a or may be stored in a memory device outside the imagesensor 200 a. In an example, the multi-sampling unit 291 a may determinethe number of times of sampling as ml when the received row processingtime RPT is greater than or equal to the first time RPT1 and equal to orless than the second time RPT2, determine the number of times ofsampling as m2 when the received row processing time RPT is greater thanthe second time RPT2 and equal to or less than the third time RPT3,determine the number of times of sampling as m3 when the received rowprocessing time RPT is greater than the third time RPT3 and equal to orless than the fourth time RPT4, and determine the number of times ofsampling as m4 when the received row processing time RPT is greater thanthe fourth time RPT4.

FIG. 11 is a block diagram of an image sensor 200 b according to anexample embodiment of inventive concepts. In FIG. 11, the same referencenumerals as in FIG, 3 denote the same elements, and therefore, repeateddescriptions thereof will not be given herein.

Referring to FIG. 3 and FIG. 11, the image sensor 200 b may include atime calculator 210 b, an ADC 230 b, and a capacitance adjusting unit292 b. In addition, the ADC 230 b may include a comparator 231 b and anoise reduction capacitor 233 b. The comparator 231 b may be the same asor similar to the comparator 231 of FIG. 3, and thus a descriptionthereof will not be given herein.

The noise reduction capacitor 233 b may be connected to the comparator231 b to perform charge-sharing, thereby reducing noise in a samplingsignal. Also, the noise reduction capacitor 233 b may performcharge-sharing during the row processing time RPT. Accordingly, thenoise reduction capacitor 233 b may perform charge-sharing with a largeramount of charge if the row processing time RPT is longer. The imagesensor 200 b according to an example embodiment of inventive conceptsmay adaptively adjust variable capacitance of the noise reductioncapacitor 233 b, based on the row processing time RPT, to reduce noisedue to the charge-sharing to a large value, e.g. the maximum.

The time calculator 210 b may receive the zoom information ZI from theimage processor 100 (of FIG. 1) and may calculate the row processingtime RPT based on the received zoom information ZI. The time calculator210 b may output the calculated row processing time RPT to thecapacitance adjusting unit 292 b. The capacitance adjusting unit 292 bmay determine a capacitance value of the noise reduction capacitor 233 bbased on the row processing time RPT.

In an example of inventive concepts, the capacitance adjusting unit 292b may determine the capacitance value of the noise reduction capacitor233 b based on a stored capacitance table T_Cap. In addition, thecapacitance adjusting unit 292 b may determine the capacitance value inproportion to the row processing time RPT. As described above, theamount of charge of the charge-sharing by the noise reduction capacitor233 b is proportional to the row processing time RPT and the amount ofcharge and the capacitance value are also proportional to each other.Therefore, the capacitance adjusting unit 292 b may maximize the amountof charge of the charge-sharing by determining the capacitance value inproportion to the row processing time RPT.

The capacitance adjusting unit 292 b may adjust the variable capacitanceof the noise reduction capacitor 233 b to the determined capacitancevalue through a capacitance control signal S_Cap. In an example, thecapacitance adjusting unit 292 b may adjust the capacitance value byadjusting an interval between electrodes of the noise reductioncapacitor 233 b.

FIG. 12 is a flowchart of a method of operating the capacitanceadjusting unit 292 b, according to an example embodiment of inventiveconcepts.

Referring to FIGS. 11 and 12, in operation S310, the capacitanceadjusting unit 292 b may receive, from the time calculator 210 a, therow processing time RPT calculated based on the zoom information ZI. Inoperation S320, the capacitance adjusting unit 292 b may determine acapacitance value for the variable capacitance of the noise reductioncapacitor 233 b based on the row processing time RPT. In an example, thecapacitance adjusting unit 292 b may determine the capacitance valuebased on the stored capacitance table T_Cap. In operation S330, thecapacitance adjusting unit 292 b may set the variable capacitance of thenoise reduction capacitor 233 b with the determined capacitance value.

FIG. 13 is a block diagram of an image sensor 200 c according to anexample embodiment of inventive concepts. In FIG. 13, the same referencenumerals as in FIG. 11 denote the same elements, and therefore, repeateddescriptions thereof will not be given herein.

Referring to FIG. 13, the image sensor 200 c may include a timecalculator 210 c, an ADC 230 c, and a capacitance adjusting unit 292c.In addition, the ADC 230 c may include a comparator 231 c, a noisereduction capacitor switch 234 c, and a noise reduction capacitorcircuit 235 c. The time calculator 210 c, the capacitance adjusting unit292 c, and the comparator 231 c may respectively be the same as orsimilar to the time calculator 210 b, the capacitance adjusting unit 292b, and the comparator 231 b of FIG. 11, and thus a description thereofwill not be given herein.

The capacitance adjusting unit 292 c may output, to the noise reductioncapacitor switch 234 c, the capacitance control signal S_Capcorresponding to the determined capacitance value. The noise reductioncapacitor switch 234 c may connect a noise reduction capacitor havingthe determined capacitance value to the comparator 231 c in response tothe capacitance control signal S_Cap. To this end, the noise reductioncapacitor circuit 235 c may include a plurality of noise reductioncapacitors having different capacitances C1 to C4.

In an example, the capacitance adjusting unit 292 c may determine thefirst capacitance C1 as a variable capacitance of the noise reductioncapacitor based on the row processing time RPT and the capacitance tableT Cap received from the time calculator 210 c. The capacitance adjustingunit 292 c may output the capacitance control signal S_Cap to the noisereduction capacitor switch 234 c to set a noise reduction capacitor tothe first capacitance C1. The noise reduction capacitor switch 234 c mayconnect the noise reduction capacitor having the first capacitance C1 tothe comparator 231 accordingly.

FIG. 14 is a block diagram of an image sensor 200 d according to anexample embodiment of inventive concepts. In FIG. 14, the same referencenumerals as in FIG. 3 denote the same elements, and therefore, repeateddescriptions thereof will not be given herein.

Referring to FIG. 14, the image sensor 200 d may include a timecalculator 210 d, an ADC 230 d, and a current adjusting unit 293 d,wherein the ADC 230 d may include a current manager 236 d. The timecalculator 210 d may be substantially the same as or similar to the timecalculator 210 of FIG. 3, and a description thereof will not be givenherein.

The time calculator 210 d may receive the zoom information ZI from theimage processor 100 (of FIG. 1) and may calculate the row processingtime RPT based on the received zoom information ZI. The time calculator210 d may output the calculated row processing time RPT to the currentadjusting unit 293 d.

The current manager 236 d may control a current consumed in the ADC 230d. Although FIG. 14 shows the current manager 236 d in the ADC 230 d,inventive concepts is not limited thereto and the current manager 236 dmay control current consumption of the ADC 230 d outside the ADC 230 d.

The current adjusting unit 293 d may output a current adjusting signalS_Cur to the current manager 236 d based on the row processing time RPTand a current table T_Cur received from the time calculator 210 d. Thecurrent manager 236 d may adjust a current of the ADC 230 d based on thereceived current regulation signal S_Cur. For example, the currentadjusting unit 293 d may adjust the current consumption of the ADC 230 dbased on the row processing time RPT. According to an example embodimentof inventive concepts, the current adjusting unit 293 d may be set suchthat the current consumption of the ADC 230 d is inversely proportionalto the row processing time RPT. In more detail, the current adjustingunit 293 d may output the current adjusting signal S_Cur set such thatthe current consumption of the ADC 230 d is inversely proportional tothe row processing time RPT, to the current manager 236 d. The imagesensor 200 d according to inventive concepts saves current consumptionin an area where current is not actually required or desired, byadaptively adjusting the current consumption of the ADC 230 d based onthe row processing time RPT according to digital zooming, therebyreducing power consumption of the image sensor 200 d.

FIG. 15 is a block diagram of an image sensor 200 e according to anexample embodiment of inventive concepts.

Referring to FIG. 15, the image sensor 200 e may include a timecalculator 210 e, a mode selector 215 e, a timing generator 220 e, amulti-sampling unit 291 e, a capacitance adjusting unit 292 e, and acurrent adjusting unit 293 e. The time calculator 210 e, the timinggenerator 220 e, the multi-sampling unit 291 e, the capacitanceadjusting unit 292 e, and the current adjusting unit 293 e mayrespectively be the same as or similar to the time calculator 210, thetiming generator 220, the multi-sampling unit 291 a, the capacitanceadjusting units 292 b and 292 c, and the current adjusting unit 293 d ofFIGS. 1 to 15, and thus a description thereof will not be given herein.

The mode selector 215 e may receive a mode selection signal S_MS fromoutside (for example, the image processor 100 (of FIG. 1), a host, or auser), and may receive the row processing time RPT from the timecalculator 210 e. The mode selection unit 215 e may output the rowprocessing time RPT to at least one of the timing generator 220 e, themulti-sampling unit 291 e, the capacitance adjusting unit 292 e, and thecurrent adjusting unit 293 e based on the received mode selection signalS_MS. In response, the timing generator 220 e may output various timingcontrol signals Cont_T to the ADC 230 (of FIG. 1) and the ramp generator260 (of FIG. 3) based on the received row processing time RPT, and themulti-sampling unit 291 e may output the multi-sampling enable signalEn_MS to the timing generator 220 e based on the received row processingtime RPT. Furthermore, the capacitance adjusting unit 292 e may outputthe capacitance adjusting signal S_Cap to the noise reduction capacitor233 b (of FIG. 11) based on the received row processing time RPT, andthe current adjusting unit 293 e may output the capacitance adjustingsignal S_Cap to the current manager 236 d (of FIG. 14) based on thereceived row processing time RPT.

FIG. 16 is a block diagram of an image processing device 10 f accordingto an example embodiment of inventive concepts.

Referring to FIG. 16, the image processing device 10 f may include animage processor 100 f and an image sensor 200 f. The image processor 100f may include a time calculator 110 f and the image sensor 200 f mayinclude a timing generator 220 f, a multi-sampling unit 291 f, acapacitance adjusting unit 292 f, and a current adjusting unit. In FIG.16, the image processing device 10 f or the image sensor 200 f includedtherein may respectively be substantially the same as or similar to theimage processing device 10 or the image sensors 200 to 200 e includedtherein described with reference to FIGS. 1 to 14 except that the timecalculator 110 f is included in the image processor 100 f.

The time calculator 110 f may receive the digital zoom command CMD_DZand calculate, based thereon, the row processing time RPT. The timecalculator 110 f may output the calculated row processing time RPT tothe image sensor 200 f. In more detail, the time calculator 110 f mayoutput the calculated row processing time RPT to at least one of thetiming generator 220 f, the multi-sampling unit 291 f, the capacitanceadjusting unit 292 f, and the current adjusting unit 293 f. In response,the timing generator 220 f may adjust timing of the ADC 230 (of FIG. 1)and the ramp generator 260 (of FIG. 3) based on the received rawprocessing time RPT, and the multi-sampling unit 291 f may output amulti-sampling enable signal to the timing generator 220 f based on thereceived row processing time RPT. Furthermore, the capacitance adjustingunit 292 f may output a capacitance adjusting signal to the noisereduction capacitor 233 b (of FIG. 11), based on the received rowprocessing time RPT, and the current adjusting unit 293 f may output acurrent adjusting signal to the current manager 236 d, based on thereceived row processing time RPT.

FIG. 17 is a block diagram of a computing system 2000 including an imagesensor 2600, according to an example embodiment of inventive concepts.

Referring to FIG. 17, the computing system 2000 may include an imageprocessor 2100, a memory device 2200, a storage device 2300, aninput/output device 2400, a power supply 2500, and an image sensor 2600.The image sensor 2600 may include image sensors according to the exampleembodiments of inventive concepts described above with reference toFIGS. 1 to 16. Although not shown in FIG. 17, the computing system 2000may further include ports capable of communicating with video cards,sound cards, memory cards, USB devices, or other electronic devices.

The image processor 2100 may perform certain calculations or tasks. Theimage processor 2100 may include image processors according to theexample embodiments of inventive concepts described above with referenceto FIGS. 1 to 16. For example, the image processor 2100 may be or mayinclude a micro-processor or a central processing unit (CPU). The imageprocessor 2100 may communicate with the memory device 2200, the storagedevice 2300, and the input/output device 2400 via an address bus, acontrol bus, and a data bus. For example, the image processor 2100 maybe connected to an expansion bus, such as a Peripheral ComponentInterconnect (PCI) bus. When receiving a digital zoom command from ahost or the like, the image processor 2100 may, according to the digitalzoom command, output zoom information and/or row processing time RPT tothe image sensor 2600 via a bus.

The memory device 2200 may store data desired, e.g. necessary, for anoperation of the computing system 2000. For example, the memory device2200 may be dynamic random-access memory (DRAM), mobile DRAM, SRAM, or anonvolatile memory device.

Chips of the memories may be implemented in the memory device 2200 usingvarious types of packages, either individually or together. For example,the chips may be packaged as a package such as a Package on Package(PoP), Ball grid arrays (BGAs), Chip scale packages (CSPs), a PlasticLeaded Chip Carrier (PICC), a Plastic Dual In-Line Package (PD1P), a Diein Waffle Pack, a Die in Wafer Form, a Chip On Board (COB), a CeramicDual In-Line Package (CERDIP), or a Plastic Metric Quad Flat Pack(MQFP).

The storage device 2300 may include a Solid-State Drive (SSD), a HardDisk Drive (HDD), a Compact Disc-Read Only Memory (CD-ROM), and thelike. The input/output device 2400 may include an input means such as akeyboard, a keypad, a mouse, etc., and output units such as a printer ora display. The power supply 2500 may supply an operating voltagedesired, e.g. required, for the operation of the computing system 2000.

The image sensor 2600 may be connected to the image processor 2100 viabuses or other communication links to perform communication. Whenreceiving the zoom information corresponding to the digital zoom commandfrom the image processor 2100, the image sensor 2600 may adjust the rowprocessing time RPT based on the zoom information, according to theexample embodiments of inventive concepts. Accordingly, the image sensor2600 according to inventive concepts may reduce noise due to the digitalzooming, and may reduce power consumption of the image sensor 2600. Theimage sensor 2600 and the image processor 2100 may be integrated on onechip or may be integrated on different chips, respectively. Thecomputing system 2000 should be understood as any computing system thatuses an image sensor. For example, the computing system 2000 may includea digital camera, a mobile phone, a personal digital assistant (PDA), aportable multimedia player (PMP), a smartphone, a tablet PC, or thelike.

While inventive concepts has been particularly shown and described withreference to example embodiments thereof, it will be understood thatvarious changes in form and details may be made therein withoutdeparting from the spirit and scope of the following claims.

What is claimed is:
 1. An image sensor comprising: a pixel arrayincluding a plurality of pixels arranged in rows and columns andconfigured to generate pixel signals from the plurality of pixels; atime calculator configured to receive zoom information corresponding todigital zooming, and configured to calculate a row processing timeavailable for processing the pixel signals from the plurality of pixelsincluded in a single row based on the zoom information; a timinggenerator configured to generate at least one control signal based onthe row processing time; and an Analog-to-Digital Converter (ADC)configured to generate pixel data by performing sampling on the pixelsignals according to the at least one control signal, wherein the ADCincludes, a comparator configured to receive a ramp signal and outputtime information by comparing the ramp signal and the pixel data, and acounter configured to covert the time information into digitalinformation.
 2. The image sensor of claim 1, wherein the zoominformation includes a digital zoom magnification, and the timecalculator is further configured to calculate the row processing time tobe proportional to the digital zoom magnification.
 3. The image sensorof claim 1, wherein the zoom information includes information on a rownumber desired for processing, the row number having changed incorrespondence with the digital zooming, and the time calculator isconfigured to calculate the row processing time to be inverselyproportional to the row number desired for processing.
 4. The imagesensor of claim 1, further comprising: a multi-sampling unit configuredto perform sampling at least two times by controlling the ADC, andconfigured to determine a number of times of sampling based on the rowprocessing time.
 5. The image sensor of claim 4, wherein themulti-sampling unit is configured to output a multi-sampling enablesignal including information on the number of times of sampling to thetiming generator, and the timing generator is configured to output tothe ADC a control signal for performing reset sampling and signalsampling for the pixel signals in response to the multi-sampling enablesignal, wherein at least one of the reset sampling and the signalsampling is performed a plurality of times.
 6. The image sensor of claim4, wherein the multi-sampling unit is configured to output a firstnumber of times of sampling based on a first row processing time and asecond number of times of sampling based on a second row processing timewhich is longer than the first row processing time, wherein the secondnumber of times of sampling is the greater than or equal to the firstnumber of times of sampling.
 7. The image sensor of claim 1, wherein theADC further includes a noise reduction capacitor having variablecapacitance, and the image sensor further comprises: a capacitanceadjusting unit configured to adjust the variable capacitance based onthe row processing time.
 8. The image sensor of claim 7, wherein thecapacitance adjusting unit is configured to adjust the noise reductioncapacitor to a first variable capacitance based on a first rowprocessing time, and adjust the noise reduction capacitor to a secondvariable capacitance based on a second row processing time which islonger than the first row processing time, wherein the second variablecapacitance is greater than or equal to the first variable capacitance.9. The image sensor of claim 1, further comprising: a read-out circuitthat receives the pixel data from the ADC, generates a generated imagedata based on the pixel data, and outputs the generated image data. 10.The image sensor of claim 1, further comprising: a current adjustingunit configured to adjust current consumption of the ADC based on therow processing time.
 11. The image sensor of claim 1, furthercomprising: a ramp generator configured to receive a ramp-control signalfrom the timing generator, generate the ramp signal, and output the rampsignal to the comparator.
 12. An image processing device comprising: animage processor configured to calculate a row processing time availablefor processing pixel signals for a plurality of pixels included in asingle row, based on zoom information corresponding to digital zooming;and an image sensor including a timing generator configured to generateat least one control signal based on the row processing time, and an ADCconfigured to generate pixel data by performing sampling on the pixelsignals according to the at least one control signal, wherein the imagesensor further includes a multi-sampling unit configured to performsampling a number of times by controlling the ADC, and configured todetermine the number of times of sampling based on the row processingtime, wherein the number of times is at least two.
 13. The imageprocessing device of claim 12, wherein the zoom information includesinformation on a row number desired for processing, the row numberhaving changed in correspondence with the digital zooming, and the imageprocessor is configured to calculate the row processing time to beinversely proportional to the row number desired for processing.
 14. Theimage processing device of claim 12, wherein the ADC further includes anoise reduction capacitor having variable capacitance, and the imagesensor further includes a capacitance adjusting unit configured toadjust the variable capacitance of the noise reduction capacitor basedon the row processing time.
 15. The image processing device of claim 12,wherein the image sensor is configured to receive the zoom informationfrom at least one of a user or a host.
 16. A computer system comprising:an image processor configured to adaptively adjust an adjusted rowprocessing time in response to receiving a digital zoom command; and animage sensor configured to sample an image according to the adjusted rowprocessing time, wherein the image sensor includes, an Analog-to-DigitalConverter (ADC) configured to sample the image by converting an analogsignal associated with the image to a digital signal associated with theimage, and a current manager configured to adjust a current of the ADCbased on adjusted row processing time.
 17. The computer system of claim16, wherein the image processor is configured to adaptively adjust theadjusted row processing time in response to receiving the digital zoomcommand from at least one of a user and a host.
 18. The computer systemof claim 16, further comprising: a memory device configured to storedata associated with the image sensor; and a power supply configured tosupply a power associated with the computer system.
 19. The computersystem of claim 16, wherein the current manager is configured to adjustthe current of the analog-to-digital converter inversely proportional tothe adjusted row processing time.
 20. The computer system of claim 16,wherein the image sensor further includes, a current adjusting unitconfigured to output a current adjusting signal to the current manager,the current adjusting unit being based on the adjusted row processingtime.